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Wiskott Aldrich syndrome

Other Names for this Disease
  • Aldrich syndrome
  • Eczema thrombocytopenia immunodeficiency syndrome
  • IMD 2
  • Immunodeficiency 2
  • WAS
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What is Wiskott Aldrich syndrome?

How is Wiskott Aldrich syndrome inherited?

What is Wiskott Aldrich syndrome?

Wiskott Aldrich syndrome is a condition that affects blood cells and cells of the immune system. It is seen almost exclusively in males.[1] The condition is characterized by a tendency to bleed easily, development of an intensely itchy, scaling skin rash (eczema), and severe recurrent infections.[2] Wiskott Aldrich syndrome is caused by mutations in the WAS gene, which is located on the X chromosome. The condition is inherited in an X-linked recessive pattern. [1] The leading treatment option for Wiskott Aldrich syndrome is bone marrow transplantation. Alternative treatments may include surgery to remove the spleen and other more conservative measures such as antibiotics, IVIG, and avoidance of foods which may cause allergic reactions.[2]
Last updated: 10/27/2010

How is Wiskott Aldrich syndrome inherited?

Wiskott Aldrich syndrome (WAS) is inherited in an X-linked recessive manner and therefore occurs almost exclusively in males.

X-linked recessive genetic disorders are conditions caused by an abnormal gene on the X chromosome.[3] The X chromosome is one of the two sex chromosomes (the other sex chromosome is the Y chromosome). Females have two X chromosomes in each cell and males have an X chromosome and a Y chromosome in each cell.

WAS is caused by mutations in the WAS gene on the X chromosome, thereby leading to a deficiency of the WASP protein, which is important in the structure and function of most blood cells.

Females have two X chromosomes, but one of the X chromosomes in each cell is "turned off" and all of the genes on that chromosome are inactivated. Females who have a disease gene present on one of their X chromosomes are carriers for that disorder. Carrier females usually do not display symptoms of the disorder because it is usually the X chromosome with the abnormal gene that is "turned off" and females have another X chromosome in each cell with a working copy of the WAS gene. 

A male has only one X chromosome, so if he inherits an X chromosome that contains a disease gene, he will develop the disease. Males with X-linked recessive disorders always pass the disease gene to all of their daughters, who will be carriers. A male cannot pass an X-linked gene to his sons because males always pass their Y chromosome instead of their X chromosome to male offspring. 

Female carriers of an X-linked recessive disorder have a 25% chance with each pregnancy to have a carrier daughter like themselves, a 25% chance to have a non-carrier daughter, a 25% chance to have a son affected with the disease, and a 25% chance to have an unaffected son.[3] This also means that each daughter has a 50% chance of being a carrier, and each son has a 50% chance of having the disease.
Last updated: 6/23/2011

  1. Wiskott-Aldrich syndrome. Genetics Home Reference (GHR). 2008; Accessed 10/27/2010.
  2. Primary Immunodeficiency. National Institute of Child Health and Human Development (NICHD). 2008; Accessed 10/27/2010.
  3. WAS Related Disorders. NORD. February 15, 2008; Accessed 6/15/2011.